build-sys: move *-setup out of shared to avoid selinux being pulled in

1 files changed, 265 insertions, 0 deletions

diff --git a/src/core/machine-id-setup.c b/src/core/machine-id-setup.c
new file mode 100644
index 000000000..9e84ac0cb
--- /dev/null
+++ b/src/core/machine-id-setup.c
@@ -0,0 +1,265 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/mount.h>
+
+#include <systemd/sd-id128.h>
+
+#include "machine-id-setup.h"
+#include "macro.h"
+#include "util.h"
+#include "mkdir.h"
+#include "log.h"
+#include "virt.h"
+
+static int shorten_uuid(char destination[36], const char *source) {
+        unsigned i, j;
+
+        for (i = 0, j = 0; i < 36 && j < 32; i++) {
+                int t;
+
+                t = unhexchar(source[i]);
+                if (t < 0)
+                        continue;
+
+                destination[j++] = hexchar(t);
+        }
+
+        if (i == 36 && j == 32) {
+                destination[32] = '\n';
+                destination[33] = 0;
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
+static int generate(char id[34]) {
+        int fd, r;
+        unsigned char *p;
+        sd_id128_t buf;
+        char *q;
+        ssize_t k;
+        const char *vm_id;
+
+        assert(id);
+
+        /* First, try reading the D-Bus machine id, unless it is a symlink */
+        fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+        if (fd >= 0) {
+
+                k = loop_read(fd, id, 32, false);
+                close_nointr_nofail(fd);
+
+                if (k >= 32) {
+                        id[32] = '\n';
+                        id[33] = 0;
+
+                        log_info("Initializing machine ID from D-Bus machine ID.");
+                        return 0;
+                }
+        }
+
+        /* If that didn't work, see if we are running in qemu/kvm and a
+         * machine ID was passed in via -uuid on the qemu/kvm command
+         * line */
+
+        r = detect_vm(&vm_id);
+        if (r > 0 && streq(vm_id, "kvm")) {
+                char uuid[37];
+
+                fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+                if (fd >= 0) {
+                        k = loop_read(fd, uuid, 36, false);
+                        close_nointr_nofail(fd);
+
+                        if (k >= 36) {
+                                r = shorten_uuid(id, uuid);
+                                if (r >= 0) {
+                                        log_info("Initializing machine ID from KVM UUID");
+                                        return 0;
+                                }
+                        }
+                }
+        }
+
+        /* If that didn't work either, see if we are running in a
+         * container, and a machine ID was passed in via
+         * $container_uuid the way libvirt/LXC does it */
+
+        r = detect_container(NULL);
+        if (r > 0) {
+                FILE *f;
+
+                f = fopen("/proc/1/environ", "re");
+                if (f) {
+                        bool done = false;
+
+                        do {
+                                char line[LINE_MAX];
+                                unsigned i;
+
+                                for (i = 0; i < sizeof(line)-1; i++) {
+                                        int c;
+
+                                        c = getc(f);
+                                        if (_unlikely_(c == EOF)) {
+                                                done = true;
+                                                break;
+                                        } else if (c == 0)
+                                                break;
+
+                                        line[i] = c;
+                                }
+                                line[i] = 0;
+
+                                if (startswith(line, "container_uuid=") &&
+                                    strlen(line + 15) >= 36) {
+                                        r = shorten_uuid(id, line + 15);
+                                        if (r >= 0) {
+                                                log_info("Initializing machine ID from container UUID");
+                                                return 0;
+                                        }
+                                }
+
+                        } while (!done);
+
+                        fclose(f);
+                }
+        }
+
+        /* If that didn't work, generate a random machine id */
+        r = sd_id128_randomize(&buf);
+        if (r < 0) {
+                log_error("Failed to open /dev/urandom: %s", strerror(-r));
+                return r;
+        }
+
+        for (p = buf.bytes, q = id; p < buf.bytes + sizeof(buf); p++, q += 2) {
+                q[0] = hexchar(*p >> 4);
+                q[1] = hexchar(*p & 15);
+        }
+
+        id[32] = '\n';
+        id[33] = 0;
+
+        log_info("Initializing machine ID from random generator.");
+
+        return 0;
+}
+
+int machine_id_setup(void) {
+        int fd, r;
+        bool writable;
+        struct stat st;
+        char id[34]; /* 32 + \n + \0 */
+        mode_t m;
+
+        m = umask(0000);
+
+        /* We create this 0444, to indicate that this isn't really
+         * something you should ever modify. Of course, since the file
+         * will be owned by root it doesn't matter much, but maybe
+         * people look. */
+
+        fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);
+        if (fd >= 0)
+                writable = true;
+        else {
+                fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
+                if (fd < 0) {
+                        umask(m);
+                        log_error("Cannot open /etc/machine-id: %m");
+                        return -errno;
+                }
+
+                writable = false;
+        }
+
+        umask(m);
+
+        if (fstat(fd, &st) < 0) {
+                log_error("fstat() failed: %m");
+                r = -errno;
+                goto finish;
+        }
+
+        if (S_ISREG(st.st_mode)) {
+                if (loop_read(fd, id, 32, false) >= 32) {
+                        r = 0;
+                        goto finish;
+                }
+        }
+
+        /* Hmm, so, the id currently stored is not useful, then let's
+         * generate one */
+
+        r = generate(id);
+        if (r < 0)
+                goto finish;
+
+        if (S_ISREG(st.st_mode) && writable) {
+                lseek(fd, 0, SEEK_SET);
+
+                if (loop_write(fd, id, 33, false) == 33) {
+                        r = 0;
+                        goto finish;
+                }
+        }
+
+        close_nointr_nofail(fd);
+        fd = -1;
+
+        /* Hmm, we couldn't write it? So let's write it to
+         * /run/machine-id as a replacement */
+
+        m = umask(0022);
+        r = write_one_line_file("/run/machine-id", id);
+        umask(m);
+
+        if (r < 0) {
+                log_error("Cannot write /run/machine-id: %s", strerror(-r));
+
+                unlink("/run/machine-id");
+                goto finish;
+        }
+
+        /* And now, let's mount it over */
+        r = mount("/run/machine-id", "/etc/machine-id", "bind", MS_BIND|MS_RDONLY, NULL) < 0 ? -errno : 0;
+        if (r < 0) {
+                unlink("/run/machine-id");
+                log_error("Failed to mount /etc/machine-id: %s", strerror(-r));
+        } else
+                log_info("Installed transient /etc/machine-id file.");
+
+finish:
+
+        if (fd >= 0)
+                close_nointr_nofail(fd);
+
+        return r;
+}